Existing 100 amp - underground service replacement

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tbakelis

Senior Member
Hello All,

In San Jose, CA here and have a question.

Here are the facts:

-existing under ground 100 amp service
-existing center feed Zinsco panel being replaced with 100 amp square D left feed panel.
-conduit is 1 1/4" EMT

My Question:

-I have to offset conduit to left side of panel. Am I allowed to cut existing conduit down and use metal flex conduit to enter panel instead of trying to offset a piece of 1 1/4" EMT perfectly?

Thanks!
 
If the conductors are service conductors and not feeders the following applies


230.43 Wiring Methods for 600 Volts, Nominal, or Less.
Service-entrance conductors shall be installed in accordance
with the applicable requirements of this Code covering
the type of wiring method used and shall be limited to
the following methods:

(1) Open wiring on insulators

(2) Type IGS cable

(3) Rigid metal conduit

(4) Intermediate metal conduit

(5) Electrical metallic tubing

(6) Electrical nonmetallic tubing (ENT)

(7) Service-entrance cables

(8) Wireways

(9) Busways

(10) Auxiliary gutters

(11) Rigid polyvinyl chloride conduit (PVC)

(12) Cablebus

(13) Type MC cable

(14) Mineral-insulated, metal-sheathed cable

(15) Flexible metal conduit not over 1.8 m (6 ft) long or
liquidtight flexible metal conduit not over 1.8 m (6 ft)
long between raceways, or between raceway and service
equipment, with equipment bonding jumper
routed with the flexible metal conduit or the liquidtight
flexible metal conduit according to the provisions
of 250.102(A), (B), (C), and (E)

(16) Liquidtight flexible nonmetallic conduit

(17) High density polyethylene conduit (HDPE)

(18) Nonmetallic underground conduit with conductors
(NUCC)

(19) Reinforced thermosetting resin conduit (RTRC)
Click to expand...

Notice (15) and the requirements it puts on flex.
 
ptonsparky said:
The conduit coming out of the ground is EMT? We would not be allowed that and would replace it with sched 80.

Other than that I have on rare occasions used flex. You would need bonding jumpers etc.
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I believe 2017 NEC allows EMT to be in contact with earth and to be direct buried. This from recollection of a discussion in a CEU class, I still don't have a copy of 2017 yet. I think the newer EMT is allegedly better suited for this then older EMT was.

I think some of the premium EMT that is out there might be better, but don't agree that it is going to last all that long in some applications.
 
I have not seen the 2017 NEC yet, but here is the 2002 NEC.

358.10 Uses Permitted.

(B) Corrosion Protection. Ferrous or nonferrous EMT, elbows,
couplings, and fittings shall be permitted to be installed
in concrete, in direct contact with the earth, or in areas subject
to severe corrosive influences where protected by corrosion
protection and judged suitable for the condition.
Click to expand...
 
The EMT is just a sleeve that stubs up in the foundation to inside the wall. It was just a way for the Utility (PG&E) to get their dB triplex into the flush mounted panel.
 
Thanks guys, yeah, the triplex wires are direct burial once they get past the 90 underground. I would be cutting EMT just above foundation and transitioning to metal flex. From what it looks like, I think I should be ok to proceed.... but you just never know with inspectors!
 
Is the equipment grounding jumper that is mentioned in 230.43 just the ground bushing on the connector within the panel. Can Someone shoot me a picture if it is something else?
 
tbakelis said:
Is the equipment grounding jumper that is mentioned in 230.43 just the ground bushing on the connector within the panel. Can Someone shoot me a picture if it is something else?
Click to expand...
Metal raceways that contain service conductors need to be bonded by other then a standard locknut. They also don't want to depend on flexible metal raceways as the bonding method - so you need a bonding jumper around your flex to bond the EMT. A pipe bonding clamp on the EMT would be fine and route the jumper into the panel and onto the grounded conductor bus. Jumper is sized as a supply side bonding jumper.
 
kwired said:
I believe 2017 NEC allows EMT to be in contact with earth and to be direct buried. This from recollection of a discussion in a CEU class, I still don't have a copy of 2017 yet. I think the newer EMT is allegedly better suited for this then older EMT was.

I think some of the premium EMT that is out there might be better, but don't agree that it is going to last all that long in some applications.
Click to expand...
358.10(A)(1) In concrete, in direct contact with the earth or in areas subject to severe corrosive influences where installed in
accordance with 358.10(B)
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358.10(B)(1) Galvanized Steel and Stainless Steel EMT, Elbows, and Fittings. Galvanized steel and stainless steel EMT, elbows, and
fittings shall be permitted to be installed in concrete, in direct contact with the earth, or in areas subject to severe corrosive influences where protected by corrosion protection and approved as suitable for the condition.
Click to expand...
The UL Guide Information for Electrical Metallic Tubing (FJMX) says the following.
Galvanized or stainless steel EMT installed in concrete on grade or above generally requires no supplementary corrosion protection. Galvanized steel EMT in concrete slab below grade level may require supplementary corrosion protection.

In general, galvanized steel EMT in contact with soil requires supplementary corrosion protection. Where galvanized steel EMT without supplementary corrosion protection extends directly from concrete encasement to soil burial, severe corrosive effects are likely to occur on the metal in contact with the soil.
Click to expand...
 
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